“I’m responsible for the seven atomic clocks that keep UK time. The clocks lose a billionth of a second a day and I adjust for that. They are fundamental to the internet, sat-nav and banking. Our radio time signal will set people’s clocks, but it’s also crucial to fire stations timing incoming calls.

“I add leap seconds to sync our clocks with the Earth’s rotation. If I didn’t, then over thousands of years, you’d eventually have midday at midnight.”